Why can't you adjust/zoom your wallpaper photo yourself?
I've been having this issue forever and every so often look it up and it seems like it may be a bug not everyone experiences? But when I choose a photo for my wallpaper there is absolutely no way I can figure out to move it side to side or zoom in in the wallpaper settings. It just gets zoomed and placed for you and that's it. It's insanely restrictive.
If anyone else is dealing with this, one way to make it work ok-ish is to go to the photo you want to use and fill it to the screen as you want it to look and then take a screenshot of it and use the screenshot to set the wallpaper. It does always zoom it in SLIGHTLY more after this so leave a small margin.